Question

If an electron can be stopped by a potential of 5 volts its kinetic energy is

Answer 1

Answer: $8.0 \times 10^{-19} J$

Explanation:

Potential required to stop an electron is known as stopping potential.

The kinetic energy is related to the stopping potential as:

$K.E=eV_s$

where, e is the charge of the electron and $V_s$ is the stopping potential.

charge of electron,$e=-1.6\times 10^{-19} C$

Stopping Potential, $V_s=5V$

Hence, the kinetic energy of the electron is:

$K.E.= 1.6\times 10^{-19} C\times 5 V=8.0 \times 10^{-19}$